Polish ultra-distance swimmer Bartłomiej Kubkowski has achieved what no one had managed before: swimming across the Baltic Sea from Sweden to Poland.

Kubkowski set off from Kåseberga in southern Sweden on Friday, 31 July. After almost 55 hours of continuous swimming and more than 160 kilometres in the water, he reached the beach in Dziwnów on Poland’s Baltic coast on Sunday evening.

During the crossing, he did not sleep, leave the water or touch either of the two support boats accompanying him. Food and drinks were passed to him from the vessels while he remained in the sea. He maintained a speed of between approximately 2.7 and 3.3 kilometres per hour despite waves, currents, cold water and mounting exhaustion.

The achievement made Kubkowski the first person in history to complete the Baltic Sea route between Sweden and Poland by swimming continuously. It was the culmination of five years of preparation and four previous unsuccessful attempts. Before entering the water this year, the Polish swimmer had announced that it would be his final attempt.

In 2022, he ended his first bid after covering 115 kilometres. A year later, he managed 116.8 kilometres, while difficult conditions forced him to abandon his 2024 attempt after 71.6 kilometres. In 2025, he came agonisingly close to success, swimming 159 kilometres and spending more than 52 hours in the water before exhaustion and deteriorating weather forced his team to stop the attempt just 11 kilometres from the Polish coast. The official Ultra Baltic Swim fundraiser documented each stage of his long struggle to complete the route.

This time, however, Kubkowski defeated both the sea and the limits of his own endurance.

Swimming for a greater cause

The Ultra Baltic Swim has always been about more than sporting records. Each of Kubkowski’s attempts has been accompanied by a fundraising campaign for the Cancer Fighters Foundation, which supports children and young people undergoing cancer treatment.

The 2026 campaign had already raised hundreds of thousands of zlotys by the time Kubkowski reached Dziwnów, with the total approaching PLN 800,000 as further donations continued to arrive. The swimmer dedicated his historic achievement to the foundation’s young beneficiaries.

Kubkowski has been involved in swimming since childhood. He began training with Medyk Giżycko in his hometown before representing Śląsk Wrocław, Kormoran Olsztyn and AZS UWM Olsztyn. During more than a decade of pool competition, he repeatedly won medals at the Polish national championships.

In recent years, he has shifted his focus from conventional pool events to ultra-distance and ice swimming. He competed at the World Ice Swimming Championships in 2022 and 2023, becoming a three-time silver medallist.

His Baltic crossing is also not his only world-class endurance achievement. In January 2025, Kubkowski set a world record for the greatest distance covered in a 25-metre pool within 24 hours. At the Koszalin Water Park, he completed 4,143 lengths and swam exactly 103.58 kilometres, surpassing the previous record by 780 metres. SwimSwam reported that his average pace was approximately one minute and 23 seconds per 100 metres.

After years of failed attempts, harsh conditions and thousands of kilometres of preparation, Kubkowski has finally completed the challenge that defined his career. His arrival on the beach in Dziwnów was not only a landmark moment in Polish sport but also the conclusion of an extraordinary charitable campaign built on perseverance, endurance and solidarity.